Aluminum and various aluminum alloys have long been used for applications in which physical strength and thermal conductivity are desired. Examples include aluminum radiators, aluminum finning on air cooled engines, aluminum finned heatsinks for electrical components, aluminum alloy thermal transfer members in heat pumps and so on.
Thermal pyrolytic graphite has a much greater thermal conductivity than aluminum alloys, but lacks the physical strength of aluminum. The thermal conductivity of thermal pyrolytic graphite is highly directional, and is much greater in directions parallel to the planes of graphene that make up the material than in a direction perpendicular to the planes of graphene.
Thermally conductive composite materials combining thermal pyrolytic graphite and another material are known. U.S. Pat. No. 5,876,831 shows thermal plugs made of pyrolytic graphite or other carbon materials inserted into cells of a honeycomb core made of aluminum or aluminum alloys. US Patent Application Publication No. 2008/0019097 shows a resin matrix surrounding strips, channels, blocks, bars, cylinders or geometric shapes such as hexagons which may be of thermal pyrolytic graphite. U.S. Pat. No. 6,131,651 shows a flexible heat transfer device having a sandwich formed by a sheet of pyrolytic graphite between sheets of metallic composition. A diffusion bond between face sheets and core material can be formed under pressure and/or temperature. Further improvements in thermally conductive composite materials are sought.